Exercise 18 Page 245

The percent proportion is a proportion that sets the ratio of a part of a whole equal to the ratio of a percent out of 100. We can represent a is p percent of wwith the given proportion. part/whole=percent/100 ⇔ a/w=p/100We can find what number's 0.9% is 36 by thinking about 0.9 as the percent and 36 as a part of the whole. Let's substitute a= 36 and p= 0.9 into the formula and solve for w using the Properties of Equality.

a/w=p/100

SubstituteII

a= 36, p= 0.9

36/w=0.9/100

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Solve for p

MultEqn

LHS * w=RHS* w

36/w* w=0.9/100 * w

FracMultDenomToNumber

a/w* w = a

36=0.9/100 * w

MoveRightFacToNum

a/c* b = a* b/c

36=0.9w/100

MultEqn

LHS * 100=RHS* 100

36* 100=0.9w/100* 100

FracMultDenomToNumber

a/100* 100 = a

36* 100=0.9w

Multiply

Multiply

3600=0.9w

DivEqn

.LHS /0.9.=.RHS /0.9.

3600/0.9=w

CalcQuot

Calculate quotient

4000=w

RearrangeEqn

Rearrange equation

w= 4000

Knowing the value of w, let's look at the completed percent proportion. 36/4000=0.9/100 We found that 3.6 is 0.9 % of 400.